HELP WITH A PREAMP DECISION

Sometimes one just needs to make an upgrade for reasons that are purely emotional. The system is Krell 402e, Veloce LS-1, Esoteric K-01, Revel Salon2, Stealth Indra IC cables, Siltech LS-100 speaker cables.

Just lately for no apparent reason the system sounds a bit harder than it used to. I believe that one's perception of a system changes over time.

I am considering exploring either new or different tubes for the Veloce. But would anyone care to recommend a new preamp for me. Before the Veloce I had a BAT Rex pre and it sounded great, but the Veloce sounded better after a long term audition period of several weeks.

But I am up for a change. . . .recommendations most appreciated.